Logtalk is an object-oriented logic programming language that extends and leverages the Prolog language with a feature set suitable for programming in the large. Logtalk supports modern code encapsulation and code reuse mechanisms without compromising the declarative programming features of Prolog. Logtalk is implemented in highly portable code and can use most modern and standards compliant Prolog implementations as a back-end compiler. As a multi-paradigm language, it includes support for modules, prototypes, classes, protocols (interfaces), categories (components and hot patching), event-driven programming, and high-level multi-threading programming. Its distribution uses a commercial friendly license and includes full documentation, portable libraries, a comprehensive set of portable developer tools, and a large number of programming examples to help get you started.